The present invention concerns a mounting jig for a pair of orthodontic retainer elements. During orthodontic treatment, the pair of retainer elements is intended for retaining, i.e. stabilizing, a pair of adjacent teeth relative to each other in a dental arch of a patient. As such, at least one pair of adjacent teeth may be stabilized in the patient's mandible (lower jaw) and/or maxilla (upper jaw). The purpose of the mounting jig is to maintain mechanically a correct spatial relationship between the two retainer elements in a pair thereof, particularly in the process of attaching the retainer elements to the adjacent teeth of the patient.
The present invention also concerns a method of maintaining a correct spatial relationship between the retainer elements in a pair thereof, particularly in the process of attaching the retainer elements to the adjacent teeth.
Orthodontic treatment generally includes a period of active treatment and a period of passive treatment. During the period of active treatment, incorrectly placed teeth are moved into correct dental positions in the patient's mouth. During the subsequent period of passive treatment, i.e. the retention period, the previously corrected teeth are to be retained in their correct dental positions using some type of dental retainer apparatus. In the retention period, orthodontic patients must wear a suitable retainer apparatus during at least a part of a day for extended periods of time, up to several years.
Retainer apparatuses according to prior art typically include removable retainers and fixed retainers.
A removable retainer may be comprised of a plastic-based retainer plate, which is oftentimes combined with steel braces and steel clamps. The removable retainer is normally used during at least a part of the day, for example when the patient sleeps. The patient therefore must learn to use and maintain the retainer plate correctly during the retention period. This, however, requires persistent action from the patient, which may prove difficult to maintain should the patient not be willing or able to do so. Moreover, a retainer plate may also lose its ability over time to maintain the teeth in their corrected dental positions, hence being inaccurate, and some tooth remobilization therefore may take place. Moreover, a retainer plate may be uncomfortable to wear and also be prone to break easily. For these reasons, removable retainer plates are unsuitable for orthodontic retention treatments lasting several years.
A fixed retainer, however, may be comprised of an orthodontic wire, also termed a retention wire. The wire is cut into appropriate lengths and adapted for the teeth requiring dental correction. A suitable dental bonding material, for example a composite material, glue or a soldering agent, is used to attach the wire directly and continuously onto the appropriate teeth. Alternatively, the fixed retainer may be comprised of an integrally molded brace attached to a bar provided with retention base fasteners that are secured to the teeth by means of a suitable bonding material. Inasmuch as a retention wire extends continuously from tooth to tooth when attached thereon, however, a fixed retainer typically obstructs the access openings between the teeth thus affected, hence obstructing the patient's ability to maintain proper dental hygiene in this dental region when using, for example, dental floss or toothpicks. This obstructing nature may have adverse effects on the patient's teeth and/or gums and also on the retainer apparatus. As such, use of dental-hygienic means may cause inadvertent detachment of some or all of the retainer apparatus from the teeth. Moreover, dental hygiene may be difficult to perform in this dental setting. Furthermore, detrimental deposits of plaque and tartar may form in response to insufficient or lacking dental hygiene.
Patent publication WO 01/82821, which corresponds to patent application PCT/NO01/00174 of Amundsen, also discloses a dental retainer device for stabilization of a pair of teeth, or groups of such pairs, in a mandible and/or a maxilla of a patient during a retention period of orthodontic treatment.
The retainer apparatus of Amundsen is comprised of a pair of individual retainer elements intended to cooperate through mutual contact when in position of use. The elements may be formed from a material suitable for dental use, for example metal, porcelain or plastics materials. In this position, each retainer element is secured individually to a corresponding dental attachment surface of one of the two adjacent teeth in the same dental arch. For securing thereof, a bonding agent such as a composite material may be used. Each retainer element is comprised of a so-called outer surface, a basal surface and an approximal surface. The two resulting approximal surfaces are formed complementary to each other. When in position of use, the two approximal surfaces provide mutual contact surfaces that are in cooperating contact and thus stabilize each other and the associated pair of teeth to which they are attached. The approximal surfaces may be of a plane shape or have some other suitable surface shape, for example a curved surface shape. As such, the approximal surfaces may have a surface shape allowing the two retainer elements to interlock when assembled in their position of use on the two corresponding, adjacent teeth.
The pair of retainer elements may also have an elliptical or rounded and rectangular circumference shape when placed in position of use on corresponding teeth. Moreover, the outer oral surface of each retainer element may be smooth and/or rounded to feel comfortable when worn on the patient's teeth.
Furthermore, the retainer elements may also be releasably attached to an applicator strip or guide strip intended for insertion between the adjacent teeth for securing the retainer elements to the teeth. This facilitates the fitting of the retainer elements onto the patient's teeth.
In view of the prior art mentioned above, the retainer apparatus of Amundsen advantageously is well suitable for long-term orthodontic retention treatment, also allowing proper dental hygiene to be carried out without jeopardizing the integrity of the apparatus. Thus, for example, dental floss may easily be applied between the retainer elements.
One disadvantage of the retainer apparatus of Amundsen, however, is the small size and two-component nature of the apparatus. This disadvantage may also apply when a guide strip is used for attaching the pair of retainer elements onto the corresponding pair of teeth. When using a guide strip, preferably the approximal surface of a retainer element is attached on either side of the strip. Upon applying the retainer elements to the corresponding teeth, some misalignment may arise between the retainer elements as they are released from the guide strip and attached to the teeth. Moreover, it may prove somewhat cumbersome to properly control the amount and positioning of dental bonding material used between the retainer elements and the teeth. These problems may require subsequent and immediate remedial actions. As such, some immediate repositioning of the retainer elements may be necessary after attachment to the teeth and prior to hardening of the bonding material. Furthermore, some of the bonding material may have to be removed from the retainer elements and/or the teeth to ensure proper functioning of the retainer apparatus thereafter.
A further need therefore exists for a device and a method for improving the precision and efficiency of attaching the pair of retainer elements onto the pair of teeth, which is the main object of the present invention.